Electronic Towel Dispenser With Additional Power Saving Mode

ABSTRACT

A hands-free towel dispenser includes a housing having an internal volume that may contain at least one roll of towel material. Within the dispenser a dispensing mechanism is in communication with a sensor system which scans for the presence of a user at a first pulse rate and initiates a dispense cycle upon sensing a user. The sensor system is in electrical communication with a control circuit which determines the time that has elapsed from the last dispense cycle and compare the elapsed time with a preset value. If the elapsed time is greater than the preset value, the control circuit configures the sensor system to scan for the presence of a user at a second pulse rate. Upon detecting a user, the control circuit initiates a dispense cycle and sets the sensor system to scan for the presence of a user at the first pulse rate.

FIELD OF THE INVENTION

The present invention relates generally to the field of “hands-free”electronic dispensers that automatically dispense a measured length oftowel material.

BACKGROUND OF THE INVENTION

Electronic towel dispensers are well known in the art, includingdispensers that automatically dispense a metered length of towelmaterial upon sensing the presence of a user. This type of dispenser hasbecome known in the art as a “hands-free” dispenser in that it is notnecessary for the user to manually actuate or otherwise handle thedispenser to initiate a dispense cycle. The control systems andmechanical aspects of conventional hands-free dispensers are wide andvaried.

Electronic dispensers are known that use an active detection systems,and generally include an active transmitter and receiver combination todetect the presence of a user within an active detection zone. Typicalsystems may include radio frequency (RF), infrared (IR) sensors, or thelike. For example, U.S. Pat. No. 6,695,246 describes an electronicdispenser utilizing an active IR sensing system. Additionally, U.S. Pat.No. 7,523,885 describes the use of active and passive detectors, and ishereby incorporated in its entirety for all purposes.

Many electronic towel dispensers rely on battery power as a primarypower source. Accordingly, conservation of battery power is an importantconcern. While efforts have been made to reduce the consumption ofbattery power in dispensers utilizing active sensing systems, thereremains an opportunity to reduce power consumption in dispensers. Thepresent invention relates to an improvement in dispensers that may beused to improve battery life.

SUMMARY OF THE INVENTION

An electronic hands-free towel dispenser is provided for automaticallydispensing a measured sheet of web material upon detection of an objectplaced within a defined detection zone. The dispenser may be batterypowered, AC powered (with an appropriate transformer and adapter), orcapable of being switched between battery power and AC power.

The dispenser includes a housing having an internal volume so as toretain at least one roll of towel material therein, and may include amain roll and a stub roll. The housing may take on any desirableconfiguration, and may include a back member and removable cover member.The cover member may be hinged relative to the back member to provideaccess to the interior volume and components of the dispenser.

The dispenser includes an electronically powered dispensing mechanismcontained within the housing for automatically dispensing the measuredsheet from the roll of towel material upon a valid detection of anobject in the detection zone. Numerous configurations of electricallydriven dispensing mechanisms are known in the art and may be configuredfor use with the present dispenser. The mechanism may include a driveroller and associated components, a pressure roll assembly, and a tearbar. The pressure roll assembly includes a pressure roll biased againstthe drive roller, the towel material passing between the pressure rolland drive roller. An opening for the towel material is defined in themodule and aligns with a dispensing opening in the housing.

The dispensing mechanism dispenses a measured length or sheet of the webmaterial, which may be accomplished by various means, such as a timingcircuit that stops the drive roller after a predetermined time.

The drive mechanism may include a drive motor and gear assembly mountedin the module, the gear assembly transmitting motive force from themotor to the drive roller. The web material passes through the nipdefined by the drive roller and pressure roller such that rotation ofthe drive roller causes the material to be advanced out through thedispensing throat of the housing. A tear bar is disposed in the throatso that a user can separate a sheet of the material by grasping andpulling the sheet across the tear bar. In an alternative embodiment, anautomatic cutting device may be provided to automatically cut the sheetof material.

The sensor may be any one or combination of well-known active sensingsystems, such as an IR or RF system that actively transmits a signalinto a detection zone and receives a return signal that indicates thatan object is within the detection zone.

The dispenser housing may include a dispensing throat in a bottomportion thereof through which the web material is dispensed, with thesensor comprising at least one transmitter and a receiver orientedwithin the housing adjacent to the dispensing throat to transmit asignal in a transmission zone that defines the detection zone below thehousing. The transmitter and receiver may be oriented with respect tothe throat such that a sheet of the web material hanging out of thedispensing throat disrupts detection of an object within the detectionzone. Thus, a sheet that is dispensed for one user but left hanging fromthe dispenser must be removed by a subsequent user before the system isenabled for a subsequent dispense sequence.

It should be appreciated that the dispenser is not limited to anyparticular style, configuration, or intended type of web material. Forexample, the dispenser may be a towel dispenser, toilet tissuedispenser, or any other sheet material dispenser.

Various methods for operation of an electronic dispenser incorporatingsuch a sensor are also within the scope and spirit of the invention. Theinvention will be described in greater detail below by reference toparticular embodiments illustrated in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of an electronic dispenseraccording to the invention;

FIG. 2 is a perspective view of the dispenser of FIG. 1 with the frontcover in its open position;

FIG. 3 is a perspective view of a removable module unit that may beutilized with the dispenser of FIG. 1;

FIG. 4 is a side view of the dispenser of FIG. 1; and

FIG. 5 is a side diagrammatic view illustrating aspects of a sensor andassociated detection zone under the dispenser housing.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, and notmeant as a limitation of the invention. For example, featuresillustrated or described as part of one embodiment, may be used withanother embodiment, to yield still a further embodiment. It is intendedthat the present invention include modifications and variations to theembodiments described herein.

Referring to FIGS. 1 through 5, an embodiment of a dispenser 10according to the invention is illustrated. The dispenser 10 includes ahousing 16 of any desired shape and configuration. The housing 16 shownin FIG. 1 includes a base 18 and a cover 22 pivotally mounted on thebase 18 so as to be movable from the closed position illustrated in FIG.1 to the open position illustrated in FIG. 2. The cover 22 includes afront wall 23 and sidewalls 27 that align with sidewalls 20 of the base18 to define an interior volume for housing the operational componentsof the dispenser 10. A roll or rolls of web material such as a main roll12 and a stub roll 14 that are to be dispensed are also included in theinterior volume of the housing. Any conventional locking mechanism 21(FIG. 2) may be provided to secure the cover 22 to the base 18. Thehousing 16 includes a bottom underside portion 25 with a throat 24 fromwhich the material is dispensed.

The dispenser configuration 10 illustrated in FIGS. 1 and 2 is merelyexemplary of any number of electronic dispenser configurations known tothose skilled in the art that may incorporate the power saving featuresand method in accordance with the invention. As such, a detailedexplanation of the structural and control features of the dispenser 10are not necessary for purposes of explanation of the invention, and willonly be discussed briefly below.

The operational components of the dispenser 10 may be mounted directlyonto the base 18 within the interior volume of the housing 16. In analternative embodiment, a dispensing module 28 (FIG. 3) is received inthe housing 16, as seen in FIG. 2, and the operational components aremounted within the module 28. The module 28 may be readily removablefrom the base 18 for servicing and/or replacing components without thenecessity of having to remove the entire dispenser 10 from its supportsurface (i.e., wall). The housing 16 may be considered as a shell intowhich the module 28 of FIG. 3 is inserted and removed. The module 28includes a frame or chassis 32 having left and right side plates 34.Within the module 28 between the side plates 34 are mounted thecomponents of the dispensing mechanism 30, which may include, forexample, a pressure roller assembly with a pressure roller 46, atransfer mechanism that may include a transfer bar 52, a throat assembly50 that defines the throat 24 and includes a tear bar 44, a drive motorand gear assembly (not visible) that rotates drive roller 38, andcontrol circuitry housed within a circuit housing 68.

Left and right main roll holders 60 are attached to the module sideplates 34, as seen in FIG. 3, and hold the main roll 12 of sheetmaterial. Stub roll holders 62 are provided for rotatably supporting thestub roll 14 in the position within the module below and rearward of themain roll 12. It should be understood that a dispenser according to theinvention need not be configured to dispense from a stub roll, and thuswould not need a transfer mechanism. The dispenser may be configured fordispensing from a single roll of web material.

The pressure roller assembly with pressure roller 46 may be housed inthe throat assembly 50 that is, in turn, mounted within the module 28.The throat assembly 50 includes a frame that may be fixed in positionwithin the module, or pivotally mounted to the module 28 to facilitateloading of new rolls of web material. The cutting or “tear” bar 44within the throat assembly 50 is disposed along the dispensing path ofthe web material upstream of the dispensing opening 24 and downstream ofthe nip between a drive roller 38 and pressure roller 46. To separate asheet of the web material that has been dispensed from the dispenser 10,a user grasps the sheet hanging from beneath the bottom portion 25 ofthe housing 16 and pulls the sheet against the tear bar 44 such that thesheet tears and separates along the line defined by the tear bar 44.

The pressure roller 46 is spring biased against the drive roller 38 suchthat the web material passing between the nip of the rollers is advancedalong the dispensing path upon rotation of the drive roller 38. Thethroat assembly 50 defines a portion of the dispensing path and theforward portion of the dispensing throat 24.

The module 28 may include an automatic transfer mechanism to transferdispensing of the web material from the stub roll 14 to a main roll 12when the web material on the stub roll 14 is nearly fully depleted. Froman operational standpoint, this transfer mechanism can operatesubstantially as described in U.S. Pat. No. 6,079,305 issued on Jun. 27,2000, with the '305 patent incorporated herein in its entirety for allpurposes. Referring to FIGS. 2 and 3, the transfer mechanism may includea transfer bar 52 with arms pivotally mounted to the module side plates34 through gearing 56. The transfer bar 52 includes a “roller” sectionthat may be defined by a central curved ribbed section 54. The section54 includes a securing mechanism, such as a barb, so that the leadingend of the web material from the main roll 12 passes over the rollersection 54 and is held by the barb while material is feed from the stubroll 14. A stub roll sensing bar 58 is pivotally mounted to the moduleside plates 34 below stub roll holders 62, and is biased towards theaxis of the stub roll holders 62 so as to track the decreasing diameterof the stub roll as it is depleted. The stub roll sensing bar 58 isconfigured with the gearing 56 that rotates upon pivotal movement of thesensing bar 58. As the stub roll is depleted, motion of the sensing bar58 is transferred to the transfer bar 52 via the gearing 56. At acertain decreased diameter of the stub roll 14, the transfer bar 52rotates to a position such that the leading end of the web material heldby the bar 52 is brought by the roller section 54 into contact with theweb material being dispensed from the stub roll causing the leading edgeof the material from the main roll to be pulled from the bar 52 andconveyed with the material from the stub roll between the nip of thedrive roller 38 and pressure roller 46. The “new” web material from themain roll 12 is dispensed simultaneously with the stub roll materialuntil the stub roll is completely depleted. If no stub roll is presentin the dispenser, the transfer bar 52 and roller section 54 contactagainst the web material dispensed from the main roll 12.

A spring biased “fuel gauge” bar 64 may be pivotally affixed to the sideplates 34 and biased towards the center of the main roll 12 such that ittracks with the decreasing diameter of the main roll 12 as the webmaterial is depleted. This bar 64 may be biased against the front side(as depicted in the figures) or the rear side of the main roll 12. Whenthe main roll 12 reaches a diameter suitable for moving the roll to thestub roll position, a pawl (not visible) on the end of one of the armsof the bar 64 causes a switch in the control circuitry to close andactivate an LED on the indicator plate 70. In this way, maintenancepersonnel are alerted that the main roll 12 is depleted and should bereplaced.

A drive motor and gear assembly includes components mounted in themodule 28, for example in a space under and behind the drive roller 38.The motor includes a drive shaft and a drive gear attached thereto thatengages the shaft of the drive roller 38. Thus, upon energizing themotor, the drive roller 38 is caused to rotate, which results inconveyance of the web material disposed in the nip between the pressureroller 46 and drive roller 38 along the conveying path and out of thedispensing throat 24.

The dispensing mechanism may be powered by batteries contained inbattery compartment 66 that is rearward of the stub roll holders 62 (seeFIG. 3). Any suitable battery storage device or location may be used forthis purpose. A conductor may be disposed below the battery compartmentthat mates with contacts on the underside of the battery compartment 66for delivering power from the batteries to the circuitry and the drivemotor. Alternatively, or in addition to battery power, the dispenser mayalso be powered by a building's AC distribution system. The controlcircuitry may include a mechanical or electrical switch that isolatesthe battery circuit upon connecting the AC adapter in order to protectand preserve the batteries.

The control circuitry also controls the length of web materialdispensed. Any number of optical or mechanical devices may be used inthis regard. In the illustrated embodiment of the dispenser 10, anoptical encoder may be used to count the revolutions of the drive roller38. The number of revolutions may be used used by the control circuitryto meter the desired length of the sheet dispensed. Other systems maytrack the running time of the motor as the control variable, or detectperforations in the web material, and so forth.

A variety of sensor systems may be utilized with the present invention.Each such system must have at least one sensor which causes the controlcircuitry to dispense a length of web material when the sensor detectsthe presence of a user.

The sensor 80 is depicted in the illustrated embodiments as one or moretransmitters and associated receiver that define a detection zone A.This active system may be any one or combination of well-known activesensing systems, such as an RF or IR sensing system. The transmittersemit an IR beam into the detection zone A, and the receiver detects IRlight reflected from an object in the detection zone A. If the amount ofreflected light is sufficient (above a detection threshold value), thecircuitry controller initiates a dispense cycle wherein the motor drivesthe drive roller 38 until the correct length of material has beendispensed. The user then grasps the dispensed sheet and pulls it forwardto tear the sheet against the tear bar 44.

The IR transmitters and receivers may be mounted on a sensor board (notshown) within the housing. Openings defined in the housing through whichthe transmitters may actively transmit. The transmitters and receiverare in electrical communication with the control circuitry within thehousing, and the transmitters continuously transmit at a pulse rate thatis dictated by the control circuitry. Preferably, the control circuitryis a microprocessor.

The dispenser of the present invention includes a sensor system that canscan for the presence of a user at varying rates. During times whenusage of the dispenser is high, the sensor system may actively scan at ahigh rate to enable delivery of a towel without any perceived delay onthe part of the user. During times when the dispenser usage is low, suchas during night or other off-peak hours, the sensor system may activelyscan at a lower rate to conserve power while still enabling a towel tobe delivered in a timely manner to the user.

The control circuitry can be configured to enable the dispenser to varythe rate at which the sensor system scans for the presence of a user.Specifically, the control circuitry may be configured to determine thetime that has elapsed from the last dispense cycle and compare thatelapsed time with a preset value. If the elapsed time is greater thanthe preset value, the control circuit may cause the sensor system toscan for the presence of a user at a second pulse rate. In someembodiments, the second pulse rate will be lower than the first pulserate which will reduce the power consumed by the dispenser. In instanceswhere the dispenser is used only during normal business hours, the powerconsumed could be reduced by 50%. In other embodiments, it may bedesirable to set the second pulse rate higher than the first pulse rate.While scanning using the second pulse rate, the dispenser will initiatea dispense cycle when a user is detected. Additionally, the controlcircuit will reset the sensor system to scan for the presence of a userat the first pulse rate once a dispense cycle has been initiated.

While many sensor systems are suitable for use with the presentinvention, sensor systems which use infrared emitters and detectors arewell-suited for use in the present invention. The rate at which theemitters emit can be adjusted by control circuitry to reduce the powerconsumed by the dispenser during times of low usage. For example, thesensor system may be configured so that the first pulse rate is set atsix IR pulses per second, and the second pulse rate is three IR pulsesper second. However, other pulse rates may be used to accommodatespecific user and dispenser requirements.

FIGS. 4 and 5 illustrate possible locations and angular orientation ofthe IR transmitters 84 within the area of throat 24. In the embodimentof FIG. 4, the sensor 80 and detection zone A are shown. In theembodiment depicted in FIG. 5, the transmitters 84 are mounted adjacentto the front wall of the dispensing throat 24 and are angled towards therear of the dispenser. The angle of the transmitters may vary widely,depending on the particular configuration of the dispenser and mountingconfigurations. In selected embodiments, this angle may be, for example,15 degrees. With this configuration, a user must purposefully placetheir hand or other object below the housing 16 and towards the back ofthe housing in order to be “detected” and initiate a dispense cycle.

It may also be desirable to provide the dispenser 10 with the capabilityto prevent a subsequent dispensing cycle if a sheet of material has beendispensed but not removed. A separate “hanging sheet” detector may beprovided and integrated with the control circuitry for this purpose.However, in the illustrated embodiment, the IR detection sensorconfiguration also serves this purpose. Referring to FIG. 5, a hangingsheet of material is represented by 86. This sheet 86 substantiallyblocks the transmission of the active IR signal from the transmittersinto the detection zone A. The web material itself does not adequatelyreflect the IR signal to the receiver so that the hanging sheet does notgenerate a valid detection signal. Thus, an object placed into thedetection zone A while a sheet is hanging is not likely to cause adispensing cycle until the hanging sheet has been removed or ispurposefully pushed out of the detection zone A.

Various control circuits and component arrays may be configured by thoseskilled in the art to accomplish the desired features of the system ofthe present invention.

It should be appreciated by those skilled in the art that variousmodifications and variations may be made to features of the dispenserdescribed herein, particularly to the mechanical and control circuitryaspects of the dispenser, without departing from the scope and spirit ofthe invention. It is intended that the invention include all suchvariations.

What is claimed is:
 1. A hands-free towel dispenser for dispensing ameasured sheet from a roll of web material, the dispenser comprising: ahousing having an internal volume so as to retain at least one roll ofweb material therein; an electronically powered dispensing mechanismcontained within the housing for dispensing a measured sheet from theroll of web material in a dispense cycle upon actuation of thedispensing mechanism; and a sensor system in communication with thedispensing mechanism, the sensor system adapted to scan for the presenceof a user at a first pulse rate and to initiate a dispense cycle uponsensing the presence of a user, the sensor system having at least onesensor in electrical communication with a control circuit, wherein thecontrol circuit is configured to determine the time that has elapsedfrom the last dispense cycle and compare such elapsed time with a presetvalue, wherein if the elapsed time is greater than the preset value, thecontrol circuit is configured to scan for the presence of a user at asecond pulse rate and, upon detecting the presence of a user, thecontrol circuit initiates a dispense cycle and sets the sensor system toscan for the presence of a user at the first pulse rate.
 2. Thedispenser of claim 1, wherein the sensor system includes an infraredemitter and detector which is capable of emitting at a first pulse rateand a second pulse rate.
 3. The dispenser of claim 1 wherein the firstpulse rate is higher than the second pulse rate.
 4. The dispenser ofclaim 1, wherein the first pulse rate is lower than the second pulserate.
 5. The dispenser of claim 1, wherein the first pulse rate is sixtimes per second.
 6. The dispenser of claim 1, wherein the second pulserate is three times per second.
 7. The dispenser of claim 1, wherein thepreset value is one hour.
 8. A method of operation for an electronichands-free paper towel dispenser to dispense a sheet of web material,comprising initiating a dispense cycle upon detection of a user andscanning for the presence of a user with a sensor at a first pulse rate;determining the time that has elapsed from the last dispense cycle andcomparing the elapsed time with a preset value; and setting the sensorto scan at a second pulse rate if the elapsed time is greater than thepreset value.
 9. The method of claim 8 wherein the sensor is an infraredsensor having an emitter and detector.
 10. The method of claim 8 whereinthe preset value is one hour.
 11. The method of claim 8 wherein thefirst pulse rate is higher than the second pulse rate.
 12. The method ofclaim 8, wherein the first pulse rate is six times per second.
 13. Themethod of claim 8, wherein the second pulse rate is three times persecond.